A. Field of the Invention
The present invention relates generally to methods of removal of a lubricious coating. In more specific aspects, the invention relates to methods of removal of aqueous polymers comprising acrylamide or copolymers thereof from a substrate comprising the application of one or more metal salts.
B. Background of the Invention
Lubricious coatings (“LC's”) generally impede a person's traversing, holding or otherwise gaining traction on a surface due to abrupt movements. One suitable use of LC's is as a non-lethal method of crowd control. Crowd and riot control is a concern for law officials at every level of government: local, national and international. Attempts at controlling unruly gatherings and defending selected areas from such crowds have resulted in physical and psychological injury to members of the law community and the crowds alike. Suitable LC's, sometimes also called anti-traction materials or ATMs, are disclosed in U.S. Application Publication Numbers 2003/0144407, 2004/0059043, and 2004/0151909.
Non-lethal weapon systems now represent an important alternative for law enforcement officials and strategic defense purposes. In order to ensure the most desirable outcome in managing crowd control, it is desired that numerous alternatives to non-lethal weapons systems be available along a force continuum, such that a non-lethal weapon suitable for a particular application may be selected based upon the nature of the threat and level of provocation. LC's provide a method of slowing, impeding and/or eliminating the forward progress and abrupt movement of rowdy crowds.
LC's may be used to slow or hinder the forward movement of others in several ways. For example, the LC may be positioned in or around an area into which it is desirable to keep others from entering. The LC may preferably be positioned on hard surfaces such as concrete, asphalt, tile, wood, compacted soils, etc. When the LC is positioned on such a surface, it is extremely difficult, if not impossible, to enter into the restricted area by traversing over or through the LC as a person or vehicle is unable to obtain traction or friction. As such, the person is unable to propel or negotiate rapid movement in any direction, forward, back, etc., since the force of friction between the body and the LC is so minuscule.
However, after use, the LC must be cleaned-up and removed. Current methods of removal of LC's include the use of high-pressure washer systems, suitably when the LC is dispersed onto a hard surface such as asphalt, brick, smooth concrete, broomed finish concrete or the like. Pressure washing with a water stream is effective. However, it is very time consuming and requires large amounts of water and effort to complete the removal process. Soft surfaces such as compacted soil or grass require the use of a tractor dozer or similar equipment and/or hand shovel and dozer as needed to mix and plow the diluted LC in the soil or into a dump truck for removal to another site. Yet another time-consuming and work-intensive LC removal method for hard surfaces uses a scraper which can be used in combination with a wet sponge or wet emery cloth pad, suitably used on smooth floor tile, smooth concrete, brick, floor vinyl, wood surfaces or the like. The process includes the use of a scraper first, then use of a wet sponge/emery cloth-pad with a 3- to 5-gallon bucket of water. Next, the sponge or pad combination is used in conjunction with the fresh bucket of water (each square foot cleaned) to repeatedly wipe the surface until all the LC is removed. This procedure is repeated until the surface is completely clean and a re-wet test shows that there is no indication of any residual surface slipperiness. As an alternative, one could opt to scrape the dry LC into a pile from these surfaces first and then follow-up with a wet sponge or wet emery cloth-pad to completely clean the surface of remaining wet LC. This however, is also a very time and work-intensive removal process.
Such cleanup methods are work-intensive and use of implements such as a scraper may permanently destroy surfaces and finishes on substrates such as vinyl, wood, tile or the like. There is currently a need for clean-up methods that require less physical force to remove the LC, thus making the process less work-intensive, less time-intensive, use less water and less likely to cause damage to the substrate upon which the LC was dispersed.